1. Field of the Invention
The present invention relates to a profile processing apparatus, a profile processing method, and a program thereof.
2. Description of the Related Art
In recent years, an image quality of color printers that use an electrophotographic technique or an inkjet technique has been improved to become equivalent to that of offset printing machines. Further, owing to the improvement in a printing speed and corresponding software to the printing workflow, the high-performance and high-end color printers can be used for the small number of printings or proof print before practical printing in an actual printing field. In such a field, naturally, a print quality, particularly of color, is highly demanded.
A printing workflow has conventionally adopted a color matching system (CMS) using an international color consortium (ICC) profile. It can be considered that there are two main purposes for using the CMS. One of them is to realize color by a printer equivalent to the color printed by a printing machine by using a profile of the printing machine as an input profile and a profile of the printer as an output profile to match the colors therebetween. Another one is, to absorb a temporal variation of the printer and an individual difference of the machine, the output profile is created every time printing is performed, and color matching is performed to stabilize the color to be output.
If the variation of the printer is extremely small, once the input and output profiles are created, output of the printer can be maintained in a state in which the input and output colors match with each other, and thus the printing workflow can smoothly proceed. However, in the actual printing field that strictly demands the color of the printer output, a minute variation of the color cannot be often accepted. Therefore, corresponding to a varied state of the printer, an operation for creating the profile occurs frequently.
To create the profile, a number (e.g., about 1,000 colors) of color patches are output by the printer, and then a great number of the color patches on output print samples are measured with a colorimeter. Afterward, based on information about measured color values, a conversion rule between a device dependent color space (e.g., cyan, magenta, yellow, and black (CMYK)) and a device independent color space (e.g., L*a*b*) needs to be regulated. Since huge numbers of data pieces of colorimetric values are needed in the color measurement, it takes much time for measuring the patches and calculating to create the profile.
Therefore, Japanese Patent Application Laid-Open No. 2006-165864 discusses an apparatus that extracts a small number of data pieces from the created profile to perform patch output and adjusts a look up table (LUT) of the profile based on colorimetric data. According to Japanese Patent Application Laid-Open No. 2006-165864, with such a configuration in which only patches corresponding to the small number of the data pieces are used, so that the time for measuring the patches and adjusting the profile can be decreased and the adjustment of the profile can be facilitated. As a result, an operation for adjusting the profile according to the state of the printer can be frequently performed.
However, only with the configuration described in Japanese Patent Application Laid-Open No. 2006-165864, an accuracy cannot be secured when the profile is adjusted.
That is because the technique discussed in Japanese Patent Application Laid-Open No. 2006-165864 takes only operations in adjustment into consideration, and a state when the profile is created cannot be grasped. Particularly, a state of a colorimetric operation cannot be recognized.
For example, if the colorimeter used to create the profile is different from the one used to adjust the profile, due to a difference between types of the colorimeters, even if the colorimeters measure the same patch, strictly same colorimetric values may not be acquired. Thus, even though adjustment is not actually needed, an unnecessary adjustment may be performed. Or, a mistake in a level of the adjustment may occur, and thus the adjustment with high accuracy cannot be performed.